Preserve QExcell print areas in XLSX

src/types.ts

@@ -26,6 +26,7 @@ export interface Sheet {
   rowHeights?: Record<string, number>;
   showGridLines?: boolean;
   zoomScale?: number;
+  printArea?: string;
   cells: Record<string, string>;
   mergedCells?: MergedCellRange[];
   hyperlinks?: Record<string, string>;